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| Solid State & LED Displays |
By the beginning of the 1970s, LED indicators started to evolve into LED displays. The earliest LED displays are constructed of dozens of small indicator-style dies, while later displays are constructed from more complicated multi-segment dies, eventually settling on the now standard practice of using a single LED with a diffuser for each segment. Simple displays were quickly joined by LED intelligent displays, which incorporated integrated circuits directly into the LED package, allowing for a progression of smaller and more complex LED devices. |
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| Monsanto MAN1 | |
Devices included in this entry: |  |
| Monsanto MAN2 | |
The Monsanto MAN-2 is considered by most to be the first bitmapped 5x7 pixel LED display. A key product in Monsanto's line of ground-breaking LED numerical displays, the MAN-2's bitmapped display area could display letters and characters that were beyond the graphical capabilities of the seven-segment MAN-1. Unlike the TIL311 and other bitmapped smart displays that would follow, the MAN2 contains no driver circuitry. External character generator logic is required to multiplex the display's many pixels. |  |
| Monsanto MAN-3 & MAN-3A | |
Devices included in this entry: |  |
| Hewlett Packard 5082-7000 | |
Hewlett Packard's 5082-7000, manufactured in 1969, is believed to be the first smart LED display (ie, a display that includes it's own decoder chip), to ever be commercially produced, as well as HP's first LED display. Hewlett Packard largely ignored the trends then current in IC fabrication and constructed the 5082-7000 in a hermetic metal bathtub package. The digits in this device are somewhat stylized--each is equipped with an extra row of LED dies to allow for the generation of more natural representations of the '4' digit. Very few displays offer this feature, as it significantly increases the number of dies necessary to display a digit. Each of the dies was placed by hand, with tweezers, by HP's team of assemblers. This helps to explain the display's original list price of $75 dollars per unit, a substantial amount of money for 1969. The display includes a built in BCD decoder, which is located above the displayed digit. The leads of this device are attached to the metal can enclosure with glass beads and an internal ceramic substrate acts as a base for the display's internal gold traces. This display was made in both white and gray ceramic versions, the white version is shown here. Note the large metal heatsink mounted under the display, which dissipates the substantial amount of heat this device generates. The 5082-7000 saw use in a historically significant device, Hamilton's 'Pulsar' first generation LED watch. In order for the bulky 7000 series displays to be fit into the watches' casing, Hamilton had special reduced-size ceramic billets constructed by a 3rd party company, which were then sent to HP for installation of the LED dies and proprietary controller ICs. Hewlett Packard 5082-7000 Datasheet (PDF, 415kb) |  |
| Hewlett Packard 5082-7001 | |
This is a three digit analogue of the single digit Hewlett Packard 5082-7000 smart display shown above. As with the device above, this display is enclosed in a hermetic metal can package and contains an extra set of LED dies for use in the display of the '4' character. The most unusual aspect of this device is the use of a separate BCD driver IC for each digit; nearly every multi-digit smart LED display uses a single chip to drive all of the digits, to save on silicon. Each digit is also installed on a separate purple ceramic wafer. The choice of a metal enclosure is not purely a cosmetic one; the heat generated by this display when in operation is not insignificant. The 1971 Hewlett Packard price guide lists a single quantity value for this display of $165, making it one of the most expensive LED displays of its time. Hewlett Packard 5082-7000 Datasheet (PDF, 415kb) |  |
| Monsanto MAN4 | |
The somewhat unusual looking MAN4 LED display was Monsanto's attempt to add a low cost option to its line of first generation LED products. Instead of being contained in a custom epoxy package, the MAN-4 is encapsulated in a standard 14-pin plastic DIP, made from red resin for visibility. This results in a hilariously small display area relative to the size of the package - the LED digit within the MAN-4 is only 4mm high. Each segment of the display is made from a single elongated LED die, bonded to a common sheet metal leadframe. The MAN-4 was a rather unpopular product, and was used in relatively few devices. |  |
| Litronix Single Digit LED Display with Magnifier (Unknown P/N.) | |
This unidentified Litronx display appears to be a direct competitor to the Monsanto MAN-4; it has the same pinouts and utilizes a similar reduced-die construction. To counteract the laughably small digit size resulting from the use of single bar elements for each digit, Litronix has equipped this display with a large built-in magnifier that dominates the front of the package. Each LED bar element has four circular active areas arranged along its length, which gives the display its bitmapped appearance. The ball bond wires are attached to each die via oblong pads located between the active LED areas. We have been unable to fully identify this part, but suspect it must date from very early in the history of LED production based on an extremely crude construction quality that leaves one wondering if these displays were made under duress in some sort of imaginary LED gulag. |  |
| Hewlett Packard 5082-7002 | |
The origins of the 5082-7002, made by Hewlett Packard, are shrouded in mystery. This LED display can be found in no price guides or parts lists of the era, and does not appear anywhere in HP's databooks. By external appearance the 5082-7002 appears to be a crude and early part, yet the date codes on the few surviving examples suggest it was released well after the Monsanto MAN-2. It certainly was not produced in commercial volumes, at least based on the scarcity of surviving examples, yet HP appears to have assigned it a part number in line with it's other commercial releases. Regardless of this displays mysterious history, the 5082-7002 is almost surely the first 5x7 LED matrix produced by Hewlett Packard. The core of the device is an array of comb-style gallium arsenide phosphide LED dies bonded to a ceramic wafer. Each die was hand-placed by an HP semiconductor tech in a tedious manual assembly process. This ceramic wafer has been mounted in a ludicrously oversized metal bathtub enclosure with fritted bead pins and a glass cavity lid. The 5082-7002's huge package size causes real problems for any designer attempting to use this display; the gap between characters is so large as to render text practically unreadable. It is unlikely this LED was ever used in any products, and few examples seem to have survived to the present day. That said, the 5082-7002 is a certainly a visually impressive LED to the modern collector, and is a unique example of the early display engineer's art. |  |
| Early Litronix Alphanumeric LED Display (Unknown P/N.) | |
This unidentified early LED is obviously manufactured by Litronix, given its appearance and logo, but otherwise we do not have much information on this part. The display has an early, primitive style of construction with a single bare die wire bonded under a large magnification lens. The alphanumeric digit illuminates with near continuous segments; unlike some other LEDs of this era, the display segments are not broken down into separate dots. The display also has a decimal point, strangely located inside two of the segment pairs instead of beside the digit. The LED die is housed in a long 20 pin DIP PCB carrier with cylindrical leads, a ponderously bulky package for such a small digit size. The height of the package effectively limits this LED to use in single-line displays; the large gap between rows on multiple line displays would border on the ludicrous. It is unlikely this device saw use in many products. |  |
| National Semiconductor NSA578 | |
The NSA578 is an example of the next step in display evolution after single digit displays like the MAN-1, as it incorporates all seven segments into a single die. Such displays were popular for early pocket calculators and watches, where the small size of the numerals did not cause a hindrance to operation. The NSA578 contains seven digits, each whole digit is etched on a single die, and soldered to a standard PCB backing. The dies' leads are connected to tracks on the PCB by fine wires, similar to the die connections used in most semiconductor chips. The display's decimal points are separate dies, each with their own PCB pad and connecting wire. Due to the small size of single-die digits, most such assemblies used an external magnifier to make the digits more readable. The NSA758 is unusual in that it does not have an external magnifier. Instead, a red plastic cover is the only barrier between the dies and the outside world. Here is an image of the display with the cover removed, which reveals the single-die digits. |  |
| Hewlett-Packard 5082-7300 Series | |
Devices included in this entry: |  |
| General Electric SSL-140 | |
One of General Electric's most well-known displays, the SSL-140 is an early seven-segment LED in a tiny surface mount package. The SSL-140 is a single die device, in that all of the segments are constructed on the same lump of silicon. The display's decimal point is a separate small cubical die located in the right side of the display area. The segments on the SSL-140's single die extend almost to the edge of the semiconductor area, a construction style common to early LED's that lowered yields and that manufacturers quickly abandoned. The SSL-140's dies are bonded to a ceramic wafer with gold leads, with an enclosing plastic cover to protect the fragile dies and bond wires. The home experimenter should be cautioned that the SSL-140 is a frail device. The bond between the leads and the ceramic wafer is not strong, and careless handling can easily dislodge the leads and break the bond wires. Collectors should exercise care when handling this LED, especially with loose examples that have been removed from their protective cardboard sleeve. |  |
| Litronix DL1416 | |
Released in 1977, the Litronix DL1416 is a sophisticated intelligent LED display which incorporates LED dies, display drivers, and character memory into a single device. The DL1416 is able to decode 6 bit TTL-level ASCII without any external components and also includes a cursor display function that can flash an indicator over a character without erasing that character from display RAM. The LED readouts themselves are alphanumeric single die chips that have been bonded to a PCB substrate and sealed under plastic magnifier lenses for improved visibility. Unfortunately the display is quite large relative to the size of the digits displayed; a bulky plastic compartment below the display area contains the CMOS logic for the display RAM and character driver. This logic compartment makes vertical tiling of the DL1416 inconvenient; fortunately multiple 1416s could still be combined horizontally into displays of any length. The DL1416 was well received by the nascent personal computer market of the late 1970s, and saw use in many products. Although Litronix quickly superseded the DL1416 with the release of the smaller and more advanced DL2416 intelligent LED in 1979, the DL1416 still enjoyed a lengthy production run with a number of different variants produced. The earliest DL1416s were manufactured using bare tinned PCBs and recycled DL416 lens components. This model was quickly replaced by the version commonly seen today, which is built on a painted gold trace PCB with the Litronix part number crudely stamped on top of the plastic chip compartment. By 1984 Litronix was producing the DL1416B, a version with a thinner PCB and a robust complete epoxy encapsulation, similar to the package style used for the DL2416 LED. Despite the DL1416B's clear superiority, it appears Litronix did not produce this variant in great quantity, given the scarcity of examples for sale in the secondhand market. |  |
| Litronix DL2416 & Hewlett Packard HPDL2416 | |
Devices included in this entry: |  |
| Litronix DL1414 & Hewlett Packard HPDL1414 | |
Devices included in this entry: Siemens DL1414 Datasheet (PDF, 365kb) |  |
| Siemens DLR2416 | |
The DLR2416, manufactured by Siemens, is a pin-compatible drop-in replacement for the DL2416 and HPDL 2416 intelligent displays shown above. Though the DLR2416 has all of the decoding and memory capabilities of the DL2416, it replaces the 17-segment single-digit dies of the DL2416 with 5x7 character matrices constructed of individual dies. This functionally enhanced display allows for the DLR2416's internal character decoder to generate a substantially extended set of characters, including lowercase, accented, and umlaut letters not available in a standard 2416. |  |
| Siemens MDL2416 | |
Most smart displays are designed to survive in a harsh world filled with filthy humans, but the MDL2416, made by Siemens, is overbuilt to ridiculous levels only needed to withstand the wrath of Enemies of the State. The MDL2416 is a military version of the venerable DL2416 smart display shown above, and is different from it's comparatively pedestrian relative in nearly every way outside of pin assignments. The MDL2416 is packaged in a very thick metal case with a hermetically sealed glass cavity lid. The individual LED dies are mounted to a ceramic substrate with gold leads, and the pins exit the display through glass frits to complete the seal. Electrically, the MDL2416 functions identically to the civilian 2416; the ASCII decoder and drivers are present and have been attached to the underside of the ceramic substrate in a special cavity provided for such. The MDL2416 may not be able to survive global thermonuclear war, but it has a much better chance of surviving the inside of an engineers pocket than lesser epoxy-clad displays. |  |
| Monsanto MAN6A / MAN601A | |
Devices included in this entry: The MAN6A is Monsanto's first attempt at marketing a LED display with a larger digit size than their earlier DIP LED displays like the MAN1A. The MAN6 utilizes the same LED dies as a MAN1, but each segment is constructed out of four dies instead of two, which doubles the displayed digit size. Even though the MAN6A is packaged in an unusual square package, it retains the same pinout and base configuration as a MAN1; one row of pins has been offset to allow the larger package to be inserted into a standard 14-pin DIP socket. The multitude of extra dies in the MAN6A made it a costly device to produce, which resulted in the displays seeing little commercial application. Monsanto also made a jumbo-sized overflow indicator to go with the MAN6A, the MAN601A. As hilarious as it may sound, the MAN601A uses the exact same number of dies as a MAN-1 series overflow indicator - the dies have simply been spread out with large gaps in order to make the size of the displayed digit match the MAN6A. The MAN601A easily ranks as one of the ugliest overflow indicators ever constructed by humanity. |  |
| Hewlett Packard 5082-7107 | |
The 5082-7107 is a large, high quality red LED bitmapped display, manufactured by Hewlett Packard. The display contains a five digit array of discrete LED dies and has no internal logic or controller; rows and columns must be manually selected and multiplexed to display a character. This display is extremely ruggedized - the white ceramic package, glass cavity lid, and all gold construction make it an impressive example of military-grade LED display construction. |  |
| Litronix Surface Mount Wristwatch LED | |
One of the first places where early LED displays were fully exploited was in the manufacture of digital wristwatches. Although 'jump hour' mechanical digital watches were already in wide use by the time LED's were first made available, the invention of the light emitting diode allowed for the creation of the first completely solid state watches. This unidentified Litronix LED display is typical of the sort of display that would have been used in such a watch. Size matters in something that has to fit on a human wrist, and this LED module goes beyond mere smallness; it is so tiny it could practically be hidden inside a traditional LED 7 segment display with room to spare. Each single die digit is only 3mm high, and the entire display face is 19mm by 5mm across. This small area leaves no room for traditional pins; the display makes use of a tiny ball grid array similar to the type used on many modern graphics card chips. Needless to say, these parts were not intended to be replaced by the home builder. |  |
| AEL 4004 | |
The AEL4004 is a obscure model of LED display with an early style of construction. Each digit is made up of an individual LED die, which has been mounted to a piece of white ceramic and encased in a plastic boat with gold leads. This display is extremely small for a 6 digit alphanumeric device; the digits are only 3mm high and the entire display is 26mm long... only slightly larger than a standard 18 pin DIP. Strangely, the package has not been designed for symmetrical side to side mounting, as there is a large border of 'dead space' on either side of the display ceramic. This probably contributed to the AEL4004's lack of success in the market, as the primary driver of LED production in the early 1970s was for use in pocket calculators, which require displays that can be mounted side-by-side in multi-package arrays. The example shown here was produced in 1974. |  |
| Soviet Opteron 3LS340A1 | |
The 3LS340A1 at first glance appears to be a Soviet analog to early US-made bitmapped displays like the MAN2. However, this Soviet display comes with a twist; each of its LED dots is not made from a separate die. Instead, a single semiconductor 'sliver' die is used for each horizontal 5-dot row, allowing the entire device to be manufactured with only seven dies. This likely made assembly of the display much easier, though it probably increased the number of 'dud' dies that had to be discarded during the manufacturing process. One semiconductor bar in each display has been produced with an extra die, to provide the display with a built in decimal point. Much like early Monsanto displays, the 3LS340A1 was made in both clear and red encased versions; the red version is shown here. The plastic encasement is a hollow cap, which is bonded to the ceramic wafer containing the LED dies and pins. A noteworthy complexity introduced by the use of mulit-dot LED sliver dies is that individual LED dots can not be binned by brightness beforehand to produce a consistent brightness between all dots in a character. In an effort to mitigate this, each dot is connected with a pair of redundant bond wires, which helps to even out brightness irregularities when multiple dots are lit at once.
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| Soviet 490IP1 | |
Have you ever wanted a smart LED display that could easily be lost in your pocket? The 490IP1 LED, produced in the former Soviet Union, is a likely contender for the smallest smart LED display in the world. This display has a built in decimal counter and 7 segment encoder etched into a single die, which can be easily seen through the LED's glass front. This display is insanely small; the digit height is only 2.5mm and this device is a tiny fraction of the size of electrically comparable decimal counter LEDs such as the Texas Instruments TIL306. The 490IP1 has a maximum counting speed of 1MHz as well as a carry output that allows multiple LEDs to be chained together. In effect, this LED can be thought of as a functional replacement for the Elesta EZ10B dekatron counting tube, though since the 490IP1 is not filled with chronically leaky hydrogen gas, it is likely a much more robust device. Since the display area of the 490IP1 is very small, the Soviets produced a companion external magnifier designed to work with this LED. The magnifier would clip to the outside of the display and provide a bubble lens over the digit area, to make the display easier to read. |  |
| Hewlett-Packard HDSP-2112 Series | |
Devices included in this entry: |  |
| Hewlett-Packard HDSP-2xxx Series | |
Hewlett-Packard HDSP-2010 red intelligent LED display (12-pin red glass-on-ceramic DIP) |  |
| Russian IPV72A-4/5x7 | |
Though the West produced single die segmented LEDs in both strip packages for calculators as well as alphanumeric smart displays like the DL2416, single die 5x7 LED arrays remained elusive. Early LEDs like the 5082-7000 used manually placed individual dies for their complex bitmapped numbers and their modern descendants continue to use individual dies for each dot, though the dies are now placed electronically. HP researchers long suspected that single die bitmap displays would be almost impossible to produce, due to the porous and conductive nature of the mask layer material. This difficult problem was overcome however, in Soviet devices like the IPV72A-4/5x7. Though at first glance the IPV72A would appear to be a bulkier clone of the Western HDSP-2000, a closer look reveals something much more interesting. Each digit in the IPV72A is constructed out of a single die, with 35 separate LED dots formed into its surface. The manufacturer appears to have solved the diffusion problem through an additional mechanical process; each vertical row of LEDs has had a trench milled or etched alongside it to isolate it from adjacent rows. Bond wires are then installed in the normal way to connect each horizontal row, with the single die providing perfect placement of each dot relative to the others in each character. Manufacturing dies of this size without any defective dots is undoubtedly challenging, and it is unknown how long it took Soviet engineers to perfect this process.
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| LITEF 104267 | |
There are few collectors or electronics enthusiasts who would not stop and stare at this very unusual device. The LITEF 104267 is a 4 digit LED smart display that has been designed for aerospace applications, and it is packaged in a unique hermetic metal bathtub enclosure. The lid of the enclosure, which has likely been resistance welded into place for an airtight seal, is equipped with four small glass windows, which allow the LED dies inside to be seen. The display also has an eighth row of LED pixels with an unknown function located below each digit. These LED dots could act as a cursor indicator on large multiple line displays, or could have been included to allow question marks and exclamation points to be drawn more effectively. Unfortunately, the LITEF 104267 is a textbook definition of an undocumented part. Even the manufacturer is in question; these displays were probably made by Northrop for use in fabulously expensive military data terminals, but there is no concrete information to confirm this. Needless to say, there are no datasheets or manufacturer specifications available, and working out the pin connections for this LED display was a harrowing task. |  |
| Hewlett-Packard HCMS-3966 | |
The HCMS-3966 is a step along the trend in the evolution of LED smart displays, designed for a world of programmable microcontrollers where no factor holds more weight than reducing the number of I/O pins needed to control a device. The HCMS-3966 is a 3.3 volt compatible serial display that works much like the earlier HDSP-2xxx devices, in that it has no character driver and data is directly shifted into registers that represent the LEDs in the 5x7 display matrix. Unlike the tedious to control HDSP-2xxx devices, the registers in the HCMS-3966 shift bits in a logical manner from right to left, making it much easier to shift data into the device. Unfortunately the 3966 is a much less TTL friendly device than the HDSP-2xxx; a built in brightness register is set to zero by default, and can only be changed by clocking in the correct serial data word into the appropriate control register. This is one device that can not be clocked and tested manually with pushbuttons. |  |
| Fairchild FND-10 | |
Fairchild's FND-10 is a small numerical display that uses a single LED die for all seven segments, similar to multi-digit displays like the NSA578. This display is extremely tiny: the width of the package is only 6mm. The FND-10 has eight pins arranged in a miniature DIP configuration with a ninth pin located in the center of the displays underside. Company literature claims that this display could be easily read from five feet away, but given the digit's tiny size and 650 microcandle light output, such claims seem wildly optimistic. |  |
| Litronix DL330 Series | |
Devices included in this entry: Litronix DL3xx series parts were second sourced by Siemens; the DL340 pictured in the thumbnail is actually the Siemens variant of the part. The Siemens manufactured parts are significantly higher quality than the Litronix units they are designed to emulate, the DL340 shown above has heavy gold traces and a substantially different package with smaller, more precisely cast magnifier lenses. |  |
| Litronix DL44M | |
The 2-digit DL44M is a fairly typical Litronix display, with a clear epoxy package and gold leads. Even with only two digits, the 12 lead package for the DL44M lacks enough pins for direct drive and each digit must be mulitplexed. The DL44M's tiny single-die LED elements are made visible by ludicrously oversized, anatomically suggestive magnification lenses. |  |
| Hewlett-Packard 5082-7400 Series | |
Devices included in this entry: |  |
| Hewlett Packard 5082-7500 | |
The problem with early LED displays, as Hewlett Packard had discovered when producing their prior LED products, is that they are simply too small. The 5082-7500 was an attempt to solve this issue, by taking a 5082-7000 LED display and replacing the tiny LED dies with standard 5mm epoxy LEDs. The 5082-7500 uses the same complicated false bitmap as HP's early 5082-7000 display, and includes an extra row of LEDs which is used to produce more accurate "4" and "7" characters. The BCD driver circuitry of the 5082-7000 has been packaged in a separate integrated circuit, which is located to the left of the display digit. We have been unable to confirm the release date of this display, but suspect it was produced sometime around 1973. As with their other early LEDs, Hewlett Packard's manufacturing excess is on full display; the 5082-7500 is resplendent with gold traces and white ceramic packaging. Given it's size and complexity, the 5082-7500 was likely an expensive part to purchase. By all measures the 5082-7500 appears to have been a commercial failure, at least in comparison to the 7400 and 7300 series LED displays that preceded it. To our knowledge it was never sold in quantity and was used in no devices of commercial significance. Interestingly Hewlett Packard does not even appear to have used the 7500 in any of it's own products, a sharp departure from their other early LED models. The home builder could probably build a very nice clock or counter from these if only they were more readily available. |  |
| Soviet AL304V | |
Most Western manufacturers abandoned the multiple die style construction of the Monsanto MAN-3 before a viable green LED chemistry was developed; nearly every LED calculator in the world uses red LED displays. The Soviets were one of the few groups still manufacturing transparent single-die 7-segment LED's at the time green LEDs were commercialized, and as such this Soviet-era MAN-3 clone is a strange beast: a green LED constructed in classic vintage single die style. The display is very nearly the same size and shape as a Monsanto MAN-3 and contains seven elongated dies for the segments and an eighth square die for the decimal point. The dies are not divided into multiple active 'dots' as in other displays of this construction style. Instead, the entire surface of the die emits light. The LED package is almost perfectly clear and the ground plate is cut to match the shape of the segments, which gives these displays a striking transparent appearance not shared by other vintage LEDs. |  |
| Surface Mount LED Display with Magnifier Lens (Unknown Mfr.) | |
This unusual device is a tiny surface mount LED display with a twist: a built in magnifier. This device can display normal seven-segment characters and has a decimal point indicator, but lacks the second ground contact common to other displays of this general form. The leads on this example are clipped, but it is likely that the display originally had quad inline leadforming based on the way the contacts have been clipped. Digit height on this display is only 1.5mm and the tiny, vaguely comical built-in magnifier lens does little to improve the size of the displayed digit. We have no idea who manufactured this strange LED, but suspect from the construction style that it was probably made by Litronix. |  |
| RFT VQC10 | |
In spite of prevailing evidence, not all LED smart displays were made by Litronix and Hewlett-Packard. RFT, based in Germany, also made smart displays such as this one, the VQC10. Packaged in an attractive red molded epoxy package, the VQC10 has four characters, each containing 35 LED dies arranged in a 5x7 matrix. Unlike many other smart displays, the VQC10 has no built in character driver or other advanced features. The display uses an extremely convoluted control scheme, rows across all digits are ganged together and controlled manually, while each column can be selected by sending a 9 bit address in parallel to the display's driver circuitry. The home experimenter should take note that the VQC10 has wider pin spacing than most DIP LED displays, and will not fit in a conventional breadboard or socket. VQC10 (VQC 10) Datasheet (PDF, 133kb) |  |
| Monsanto MAN2185 & DL2185 | |
Devices included in this entry: Litronix manufactured a second-source version of this part, the DL2185. The DL2185 is nearly identical to the MAN2185, but replaces the linear magnifier of the Monsanto display with discrete bubble magnifiers for each digit. |  |
| RCA TA-8032 | |
The TA-8032 is a pre-production laboratory sample of the (then brand new) RCA liquid crystal technology, which would eventually take over the world in everything from wristwatches to televisions. This display was made in October of 1970, and predates the release of the first LCD products by several months. In effect, this is one of the first complete LCDs ever made, and it is very different from a modern liquid crystal display in both package and function. The most noticeable feature of first generation LCD technology is the inverted display; unlike a modern LCD which displays a black digit on a white background, early LCDs display white digits and must be mounted to a dark background to be legible. The glass envelope on the TA-8032 is so bulky compared to the size of the displayed digit that it borders on the ridiculous, RCA would have never released a display in such an impractical package for use in commercial products. The two metal posts on the front of the display may appear as though they are intended to hold the two halves together, but they actually cover the fill and vent tubation that would have been used during manufacture to pump the liquid crystal material into the display. It should be noted that LCDs which used this early dynamic scattering mode technology were very failure prone, and few have survived to the present day. The first practical LCD display did not arrive until 1973 when Sharp first released calculators based on its new and more reliable COS LCD technology. |  |
| Texas Instruments TIL302 | |
The humble TIL302, produced by Texas Instruments, is one of the most popular and heavily used early LED display types. First produced in the early 1970s, the TIL302 has been in continuous production for decades. Few would suspect that such a common device could be interesting, but the TIL302 went through a number of dramatic design changes during the first years of its production. The earliest TIL302s are constructed out of individual bar dies mounted to a fiber carrier with gold traces and leads, which is then sealed in clear epoxy. All of the traces outside the digit area are painted with black paint. This results in a very attractive display, but was likely expensive to manufacture and TIL302s of this style were only produced for a short time prior to 1972. Starting in 1972 TIL302 displays were produced with tinned pins and traces and no black paint overlay, which saved on cost but resulted in a singularly hideous appearance. Texas Instruments quickly converted to a third version of the display, which introduced the now standard red cast epoxy and ceramic PCB common to all of Texas Instruments early LED displays. This version was a success, and TIL302 displays of this style were produced in huge quantities. Texas Instruments also produced a military grade variant of this display, which used identical LED dies, but was encased in a ceramic bathtub package with a glass lid and bottom braised pins. |  |
| Texas Instruments TIA8447 | |
The TIA8447 is a nearly modern incarnation of Texas Instruments' backbone TIL302 seven segment display. The TIA8447 features a ruggedized package with a hermetically sealed glass-and-ceramic carrier and gold leads. The unit is a 'dumb' display; it contains no driver circuitry and all such functions must be supplied with external logic. The TIA8447 has identical pinouts to the TIL302, making it a drop-in replacement. |  |
| Texas Instruments TIL311 | |
The Texas Instruments TIL311 is the definitive example of hexadecimal smart display technology. Used in innumerable electronic systems over the years, the TIL311 contains a BCD decoder and a hexadecimal character set in addition to its LED elements. The TIL311 is larger than HP's competing 7300 series of displays, but can still be inserted into a standard DIP socket. The TIL311 is so popular that they are still manufactured to the current day, and see use in a number of short-run industrial control systems and test fixtures. The TIL311 is such a popular part that it has been second-sourced by numerous vendors over the years. The example shown in the thumbnail is a Hewlett Packard HTIL-311A, which is a drop-in replacement for the TIL311. The HTIL-311A includes numerous production enhancements, including an attractive cast plastic cover and a pin-1 locator molded into the surface of the display face. |  |
| Texas Instruments TIL306 & TIL307 | |
Devices included in this entry: |  |
| Texas Instruments TIL308 | |
Though the Texas Instruments TIL308 appears externally identical to TIL306, internally it is quite different. The TIL308 lacks a built in decade counter, instead it accepts BCD hexidecimal data directly, a much more flexible arrangement. The TIL308 family was in fact both the forerunner and quickly superseded by the smaller and much more popular TIL311 BCD display shown below, and as such saw limited use. The TIL308 includes several features not found in the TIL311 however, including a built in display test function as well as data outputs for the display's built in latch. Several extra pins are present on the bottom of the package in order to provide access to these additional functions. Texas Instruments TIL308 Datasheet (PDF, 117kb) |  |
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